The present disclosure relates to a fixing device fixing a toner image onto a recording medium and an image forming apparatus including the fixing device.
Conventionally, an electrographic image forming apparatus, such as a copying machine or a printer, includes a fixing device fixing a toner image onto a recording medium, such as a sheet. In the fixing device, a “heat roller manner” is widely applied in viewpoints of heat efficiency, safety and others. The heat roller manner is a manner using a pair of rollers to form a fixing nip. On the other hand, a “belt manner” recently attracts attention due to requests of shortening of a warm-up time, energy saving or others. The belt manner is a manner using a fixing belt to form the fixing nip.
For example, there is a fixing device including a fixing belt, a heating member fixedly arranged so as to face to an inner circumference face of the fixing belt, and a heat source fixedly arranged inside the heating member. In such a conventional technique, it is configured so that the heating member is heated by radiant heat of the heat source and the fixing belt is heated by the heating member.
In the above-mentioned conventional technique, because a gap is arranged between the inner circumference face of the fixing belt and heating member, there is a high possibility that contact of the inner circumference face of the fixing belt with the heating member becomes insufficient. If the contact of the inner circumference face of the fixing belt with the heating member thus becomes insufficient, it is not possible to efficiently carry out heat transfer from the heating member to the fixing belt. According to this, a problem that temperature rising rate of the fixing belt is lowered and a problem that the temperature of the heating member is excessively risen are caused in the warm-up. If the temperature of the heating member is thus risen excessively, there are possibilities that grease interposed between the fixing belt and heating member is vaporized and the heating member is deformed.